MOSSKS WITH A HAND-I,KNS 



Figure i. 

 Peristome of Orthotrichum callistomnm (From Bry. Eur.) 



6, and 7, is very similar to that of Ceratodon, only the teeth are 

 broader and less incurved when dry. 



In Fontinalis. which is always submerged, the peristome 

 consists of a network, through the meshes of which the spores 

 gradually escape. In a European moss, Orthotrichum callis- 

 tomum Fisch., the inner peristome is a domelike structure with 

 apertures near the base which are opened and closed by the 

 hygroscopic teeth of the outer peristome. 



This last is so curious yet so beautifully adapted for its work 

 that it seems almost like a fairy tale, and would be scarcely 

 credible if told of some rare unknown tropical plant instead of 

 having been seen and described by several of the most matter- 

 of-fact botanists. A somewhat similar arrangement is found in 

 Cinclidium stygium. 



